Katharine MacCloskey Crocker, 70, a resident of the Washington area for more than 35 years, died Sunday at her winter home in Naples, Fla., of coronary arteriosclerosis.

Mrs. Crocker was born in Pittsburgh. She attended Wellesley College, Wellesley, Mass., and graduated from the Pennsylvania College for Women, now Chatham College. She moved to the Washington area in 1942 with her husband the late Samuel Boone Crocker, an insurance executive.

She was an enthusiastic golfer here and in Pittsburgh. She was a member of the U.S. Senior Women's Golf Association; of the Chevy Chase Club; the Bald Peak Colony Club, Melvin Village, N.H.; the Farmington County Club, Charlottesville, Va.; the Hole-in-the-Wall, Naples, Fla., and the Naples (Fla.) Yacht Club.

Mrs. Crocker and her husband lived in Washington for many years. They later lived in Chevy Chase. Mrs. Crocker moved in Sumner Md., following her husband's death in 1975.

She was a member of the Chevy Chase Presbyterian Church.

Survivors include two daughters, Martha C. McManus, of Potomac, and Katharine B. Brocker, of Washington.

The family suggests that expressions of sympathy in the form of contributions to the Organ Fund of Chevy Chase Presbyterian Church. 1 Chevy Chase Circle, Washington, D.C., 20015.